The United Kingdom will be the first country where consumers can buy the drug Viagra without having a prescription, the drug's maker, Pfizer, announced Tuesday.

The UK's regulatory body, the Medicines and Healthcare products Regulatory Agency, said the reclassification moves the erectile dysfunction drug from a prescription-only medication to a pharmacy medication.

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The move is expected to help clamp down on unregulated sales of the popular drug.

"Erectile dysfunction medicines are a popular target for criminals selling unlicensed and counterfeit medicines," the regular agency said in its announcement. In the past five years, it has seized more than $66 million (50 million British pounds) in unlicensed and counterfeit medicines for erectile dysfunction, it said.

"Making this medication more widely available will help direct men who might not otherwise seek help into the healthcare system and away from the risks that come with buying medicines from websites operating illegally," the announcement said.

In a statement, Pfizer said that over-the-counter sales will begin in the spring to men 18 and older with erectile dysfunction after a consultation with a trained pharmacist. Men who have severe cardiovascular disorders or are at high risk of one, those with liver or severe kidney failure, or those who are taking medications that could interact will still need to see a doctor.

The drug will be sold as Viagra Connect, a 50-milligram tablet with the same active ingredient as the current prescription drug. The original Viagra, available in 25 milligrams, 50 milligrams and 100 milligrams, will still require a prescription.

The drug can cause side effects including headache, heartburn, diarrhea, nosebleeds, difficulty sleeping, muscle aches, changes in vision and sensitivity to light, according to the National Library of Medicine. Numbness, tingling or burning in arms, hands, feet or legs may also occur. More severe side effects can include an erection lasting more than four hours, chest pain, shortness of breath, vision loss, dizziness, fainting and ringing in the ears. Patients who experience any of these symptoms associated with Viagra should contact a doctor.

The little blue pill, as it's familiarly known, was created by British scientists at Pfizer in 1989 under the chemical name sildenafil citrate as a heart medication for the treatment of high blood pressure and angina, a type of chest pain associated with coronary heart disease. In early clinical trials, the drug did not prove successful, but study participants reported an increase in erections. This prompted research into using the drug as a treatment for erectile dysfunction.

Viagra was approved by the US Food and Drug Administration in 1998. It has been used by more than 37 million men since then, according to Pfizer.